The Compute and Block Storage APIs have resource usage limits.
Compute v2, Block Storage v1
Show compute and block storage limits
os limits show
    --absolute [--reserved] | --rate
    [--project <project>]
    [--domain <domain>]
Show absolute limits
Show rate limits
Include reservations count [only valid with --absolute]
Show limits for a specific project (name or ID) [only valid with –absolute]
Domain the project belongs to (name or ID) [only valid with –absolute]